We propose to acquire a commercial photoacoustic imaging system for small animal imaging in vivo and in real time. This instrument (the VisualSonics Vevo LAZR system) will be housed and managed by the existing Animal Physiology Core at Emory-Children's Pediatrics Research Center and open to the use by all investigators in additional to the major users listed in the proposal. As such, procurement of this shared instrument will support the ongoing efforts of a large group of NIH-funded investigators at Emory University and the Georgia Institute of Technology, as well as many other institutions in the Atlanta metropolitan and the southeast region. This application also reflects strong commitment of the institute administration in the form of financial support to cover operation shortfalls, service contract, and consumable supplies.